1. Field of the Invention
This invention relates to the sheet metal nails and the method for producing same and more particularly relates to improvements in sheet metal roofing nails for use in roofing structures and the like in which the sheet metal nail is driven into a thickness of sheet steel or other sheet metal to secure a pad or layer of insulation or similar material thereto.
2. Description of the Prior Art
Sheet metal nails such as sheet metal roofing nails are well known in the prior art. Such nails are generally "T" or "L" shaped comprising a generally flat head portion and a shank portion extending generally perpendicularly from the head portion. The shank portion typically has a generally flat, V or arcuate cross-sectional shape and has a generally V-shaped or other pointed leading edge designed for piercing at the end thereof most distant the head portion. The shank portions are generally provided with at least one locking member, or tang, for lockingly engaging the underside of the media into which the nail is driven. Many nails utilize one or more axially extending columns of tangs having tangs spaced at various distances from the head portion to provide locking of the nail when utilized with various thicknesses of insulation material and/or roof decks and the like. Examples of the prior art devices may be seen by reference to U.S. Pat. Nos. 2,404,245; 2,620,705; and 2,751,052.
The sheet metal nails of the prior art have been less than totally satisfactory as the head portions thereof have been relatively complicated and/or expensive to manufacture and/or did not provide a desired strength and/or surface area for driving of the nail or retaining the material through which the nail was driven. The above drawbacks are particularly troublesome in connection with relatively long, heavy duty nails utilized for securing relatively thick layers of insulation or similar roofing materials to a sheet metal roofing deck or the like.